CHAP, iv.] THE CRUISES OF THE 'PORCUPINE? 149 



or one might rather say glowing, up to the centre; 

 then that would fade, and a denned patch, a centi- 

 metre or so long, break out in the middle of an arm 

 and travel slowly out to the point, or the whole five 

 rays would light up at the ends and spread the fire 

 inwards. Very young Ophiacanthce, only lately rid 

 of their ( plutei/ shone very brightly. It is difficult 

 to doubt that in a sea swarming with predaceous 

 crustaceans, such as active species of Dorynchus and 

 Munida with great bright eyes, phosphorescence 

 must be a fatal gift. We had another gorgeous 

 display of luminosity during this cruise. Coming 

 down the Sound of Skye from Loch Torridon, 

 on our return, we dredged in about 100 fathoms, 

 and the dredge came up tangled with the long 

 pink stems of the singular sea-pen Pavonaria qua- 

 drangularis. Every one of these was embraced and 

 strangled by the twining arms of Aster onyx loveni, 

 and the round soft bodies of the star-fishes hung from 

 them like plump ripe fruit. The Pavonaria were 

 resplendent with a pale lilac phosphorescence like 

 the flame of cyanogen gas ; not scintillating like the 

 green light of Ophiacantha, but almost constant, some- 

 times flashing out at one point more brightly and 

 then dying gradually into comparative dimness, but 

 always sufficiently bright to make every portion of a 

 stem caught in the tangles or sticking to the ropes 

 distinctly visible. From the number of specimens of 

 Pavonaria brought up at one haul we had evidently 

 passed over a forest of them. The stems were a metre 

 long, fringed with hundreds of polyps. 



Ophiocten sericeum, FORBES, and Ophioscolex pur- 

 purea, D. and K., were likewise very common, and 



